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Interface engineering has led to significant progress in solution-processed CdTe nanocrystal (NC) solar cells in recent years. High performance solar cells can be fabricated by introducing a hole transfer layer (HTL) between CdTe and a back contact electrode to reduce carrier recombination by forming interfacial dipole effect at the interface. Here, we report the usage of a commercial product 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro) as a hole transfer layer to facilitate the hole collecting for CdTe nanocrystal solar cells. It is found that heat treatment on the hole transfer layer has significant influence on the NC solar cells performance. The Jsc, Voc, and power conversion efficiency (PCE) of NC solar cells are simultaneously increased due to the decreased contact resistance and enhanced built-in electric field. We demonstrate solar cells that achieve a high PCE of 8.34% for solution-processed CdTe NC solar cells with an inverted structure by further optimizing the HTL annealing temperature, which is among the highest value in CdTe NC solar cells with the inverted structure.

Solution-processed hybrid solar cells have been well developed in the last twenty years due to the advantages of low cost, low material-consuming and simple fabricating technology. However, the performance, stability and film quality of hybrid solar cells need to be further improved for future commercial application (with a lifetime up to 20 years and power conversion efficiency higher than 15%). By combining the merits of organic polymers and nanocrystals (NC), the reasonable design of interface engineering and device architecture, the performance coupled with stability of hybrid solar cells can be significantly improved. This review gives a brief conclusive introduction to the progress on solution-processed organic/inorganic semiconductor hybrid solar cells, including a summary of the development of hybrid solar cells in recent years, the strategy of hybrid solar cells with different structures and the incorporation of new organic hole transport materials with new insight into device processing for high efficiency. This paper also puts forward some suggestions and guidance for the future development of high-performance NC-based photovoltaics.

Background: Insomnia is a global public problem, which has a significant negative impact on both physical and mental health, while increasing the economic burden placed on both sufferers and society. Western medicine has a fast treatment on sleep, but it leads to side effects and strong dependence. Long Dan Xie Gan Tang(LDXGT) is a representative Chinese herbal medicine for the treatment of insomnia especially which has a bad-tempered symptom, and its effectiveness and safety has been validated clinically. However, there is yet to be any evidence-based medicine. Therefore, the effectiveness and safety of LDXGT in the treatment of insomnia are studied and systematically evaluated in this study. It will provide a theoretical support for the treatment of insomnia compared to western medicine. Objective: The study is purposed to evaluate the effectiveness and safety of LDXGT for the treatment of insomnia. Methods: Search was conducted for various databases including Pubmed, Chinese Biomedicine Database(CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), and Wan-fang. Randomized-controlled trials (RCTs) were identified for insomnia treatment involving LDXGT and LDXGT combined with ordinary Western medicine. The quality of literature was evaluated by Cochrane assessing tool to reduce the risk of bias. RevMan 5.3 software and STATA 12.0 software were applied to perform the meta-analysis. Results: Thirteen studies involving 1181 participants were identified in this systematic review. Few studies described the details of random principle. No placebo was involved in treatment. LDXGT was compared with ordinary Western medicine in 11 trials and with LDXGT combined with conventional Western medicine in 2 trials. The results of our meta-analysis showed the relative benefits in effective rates compared with conventional western medicine. (Odds Ratio [OR]= 4.32, I2 = 0%,95% confidence interval CI [3.05 to 6.13], P

The use of solution-processed photovoltaics is a low cost, low material-consuming way to harvest abundant solar energy. Organic semiconductors based on perovskite or colloidal quantum dot photovoltaics have been well developed in recent years, however, stability is still an important issue for these photovoltaic devices. By combining solution processing, chemical treatment, and sintering technology, compact and efficient CdTe nanocrystal (NC) solar cells can be fabricated with high stability by optimizing the architecture of devices. Here, we review the progress on solution-processed CdTe NC-based photovoltaics. We focus particularly on NC materials and the design of devices that provide a good p&ndash, n junction quality, a graded bandgap for extending the spectrum response, and interface engineering to decrease carrier recombination. We summarize the progress in this field and give some insight into device processing, including element doping, new hole transport material application, and the design of new devices.